For the last two years, the NYPD has conducted a special sting operation to catch thieves.

In the operation dubbed "Lucky Bag," undercover officers ride the subways and drop cell phones, iPods, or wallets. If the passerby or fellow strap-hanging subway rider returns the wallet or electronic device, he or she is thanked. If he or she decides to keep the object, police take action.

This year the sting caught 300 people and resulted in 100 arrests. Police say that 58 of the people arrested had rap sheets.

Last year the operation resulted in 188 arrests and 101 of those people had been arrested previously for another offense.

People are only arrested if it's clear that they don't intend to return the property to the person who dropped it. For example, if the person who picks up the wallet pockets the cash, then he or she is getting hooked up.

People who pick up the wallet but don't remove the cash or return it to its rightful owner are stopped, frisked, and their IDs are checked.

Police told the Daily News that for almost every person arrested, someone was honest enough to return the property.

The operation has its critics, but police say that it has significantly reduced the number of subway grand larcenies by 50 percent. In New York, theft of a wallet with a credit card with a value of $1,000 or more is considered grand larceny.

Wallets used in Operation Lucky Bag do not contain credit cards.